The present invention relates to a heat shield for a combustion chamber, particularly for an annular combustion chamber of a gas turbine, having a passage opening for a fuel injector, by way of which fuel as well as combustion air arrives in the combustion chamber while forming a swirl, as well as having a plurality of effusion holes where their central axes are inclined toward the heat shield surface and by way of which the cooling air can penetrate from the rear in order to apply a film of cooling air to the hot surface.
A heat shield provided in the head of a combustion chamber is conventionally used for protecting the dome-shaped combustion chamber head area or the front plate provided therein as well as the fuel injector itself from the effect of the hot gas situated in the combustion chamber and from an excessive heat radiation. In order to be able to carry out this function, the heat shield itself must be cooled. For this purpose, the conventional heat shields have so-called effusion holes so that cooling air can penetrate from the rear in order to apply a cooling air film to the hot surface of the heat shield.
However, because it is not always possible to sufficiently cool all vulnerable zones of the heat shield according to the state of the art, an object of the invention is to provide measures for achieving an improved heat shield cooling.
For achieving this object, a surface sector is assigned to each corner area of the heat shield which extends into this corner area. The central axes of the effusion holes in these surfaces sectors are oriented in parallel to one another and essentially toward the assigned corner area and, in sections, extend approximately in the same direction as the fuel combustion air swirl in this sector. The surface sectors are separated from one another by one transition zone respectively having effusion holes whose central axes extend essentially in parallel to one another. The surface sectors, together with the transition zones, form the total surface of the heat shield.